Oh my god i'm so sorry
Do you have an understudy?
Are you drinking tea with honey? That usually helps with sore throats. I've heard at theater that dairy and lots of coffee and sugar can kill your voice, too. Please rest and take care of yourself, you'll recover faster if you go easy on yourself. I'm not an actor, so take this with a grain of salt, but i'd suggest avoiding talking as much as possible, run through your lines in your head not out loud. You probably already know a lot of this, but i hope something helps
Good luck, hope you feel better soon <33